A service is in use that delivers at cost digital contents to a user terminal such as a computer or a portable telephone set from a content delivery service server connected to a network such as the internet. Delivered contents include music and game software contents. In this service, a purchaser accesses a content delivery site and selects desired contents from a variety of contents serviced by the site.
However, the aforementioned related art system assumes that a purchaser selects a content delivery service server to purchase a desired content. This does not raise the user's appetite for purchasing contents.
The invention aims at providing a system where additional services using other sites connected over a network are made available when a content is delivered from a specific content delivery service server, thus raising the user's appetite for purchasing contents by using a specific server.